The question Are Online Certs worth their weight? made me wonder if there are any open source training materials for GIS.

By this I don't mean training specifically for open source software - of which I know there are some - but a set of general training materials for GIS and geographic data that are developed as an open source project.

i.e. a set of training materials that are community developed, freely available, and with an open license. That anyone could take and use for general GIS training.

If there isn't, does anyone think this would be a worthwhile project?

Please add license info for the material you're suggesting.